Re: TRIAC dimmer control spreadsheet; was Re: Controlling Holiday Lights

[nobody@xxxxxxxxxxxx (Dave Houston)]

"Max" <nospam@xxxxxxxxxxx> wrote:

>I have done some playing around with this and found that in order to change
>the intensity of a light very very slowly, without seeing any noticeable
>step
>in brightness (especially noticeable at the lower brightnesses) you need
>each
>change in time to be around 10us or so.  This means for the criteria
>mentioned,
>you would need many hundreds of steps, likely about 500 or so.  I would
>consider a 100 step dimmer marginal and a 256 step minimum.  But that is
>just my preference :-)
>

Sending a single DIM or BRIGHT code to an X-10 LM465 lamp module results in
an average change of about 0.662% as measured with a Kill-A-Watt (a 100W
bulb makes things simple) and with a true RMS voltmeter. 146 steps will take
the lamp from one extreme to the other. (It varies a bit with other models
of lamp modules.)

     http://davehouston.net/micro-dim.htm

Using a 25W R14 lamp in a spotlight type holder, it is easy to discern
individual steps on the low end either by looking at the light projected
onto a surface or, at the very lowest levels, looking at the filament
itself.

With a 100W bulb in a standard table lamp, individual 0.662% steps result in
larger increments in light level that, again, can be discerned by looking at
the light hitting the ceiling or looking directly at the filament at very
low levels.

I think that most people would not find the changes annoying - they are not
readily perceived unless you are watching for them and, even then, only if
the steps are fairly close in time. But, it will depend on the eye of the
beholder.


http://davehouston.net
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